I used to be the general counsel for a medium-sized publicly-traded software vendor. Before I would even look at a customer's software license agreement form, I had the sales people arrange a five-minute phone call between me and the customer's contracting people. I was usually able to sell the other side on using our form (because our form was extremely customer-friendly). Even when we wound up using the customer's form, though, that first phone call helped establish a positive working relationship, which softened the blow when I sent the customer a redline of their form.
(Not to try to divert attention, but I did an http://www.drafterschoice.com/2008/11/how-to-kill-a-big-comp... of the above comments at http://www.drafterschoice.com/2008/11/how-to-kill-a-big-comp...)
However, lots of good advice here, including some that involves little company / big company negotiating tactics.